Good
correlation was noted between NDVI readings and grain yield (grams/2.4m2,
2 rows, 0.75m *1.6m), largely because there was a wide range in yield
differences (3000 to 8000 kg/ha). Normally, it is more difficult to
observe large differences in breeding nurseries, simply because most are
advanced lines and all have good yield potential. However, in the
winter of 2002 at El Batan, there was a significant infestation of yellow
rust. Thus, it may well be that the sensor was useful in detecting
stress as a function of disease.

It is important to note that we did not
find any correlation between NDVI readings and yield in the other
nurseries sensed where yield levels were high, and where no disease
symptoms were present. Thus, the sensor may be useful for 'rust' and
other disease nurseries, but not for detecting subtle differences in yield
when all lines are between 6000 to 8500 kg/ha.